# CVE-2026-80995: linux: In the Linux kernel, the following vulnerability has been resolved:  net: mctp: hold a reference to the route device...

CVE-2026-80995 is fixed in linux on 1 platform by DEBIAN-CVE-2026-80995 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-80995
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0017
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 11, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  net: mctp: hold a reference to the route device in mctp_route_lookup()  mctp_route_lookup() uses rt->dev without holding a reference on it. mctp_route_lookup_single() returns the route under RCU only, so the route's device can be torn down concurrently: mctp_dev_put() drops the last reference and synchronously kfree()s mdev->addrs.  mctp_dev_saddr() then reads rt->dev->addrs[0], giving a use-after-free reachable by an unprivileged local AF_MCTP user on the receive/forwarding path (no CAP_NET_RAW required):    BUG: KASAN: slab-use-after-free in mctp_route_lookup   Read of size 1 at addr ... by task mctp_uaf/...    mctp_route_lookup    mctp_pkttype_receive   Freed by task ...:    kfree    mctp_dev_put    mctp_dev_notify  In the same window mctp_dst_from_route() -> mctp_dev_hold() also increments a refcount that has already reached zero ("refcount_t: addition on 0 ... mctp_dev_hold").  This reintroduces the use-after-free class of CVE-2023-3439: the source address lookup was moved ahead of the point where the destination takes its device reference.  Take a reference with refcount_inc_not_zero() before touching rt->dev, skip a device that is already dead, and drop the reference once the destination has taken its own.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-80995](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80995.md) | Sep 23, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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